The three main credit ratings agencies—Moody's, Fitch and Standard & Poor's—are heavily influencing fiscal policy in the eurozone and the United States. Objectively, this is madness. That is what finance ministries and departments are for. Still, the credit ratings agencies are not to be blamed for the debt crises in the euro area or the US.

Why do we care what they say?

Having completely dropped the ball and failed to predict the global financial crisis that kicked off in 2008, the main three credit ratings agencies lost significant credibility. Rather than rely on the big ratings agencies, a number of buy-side investment firms have established their own research teams.

If the credit ratings agencies have been asleep at the wheel and investors are doing more of their own research in-house, why does anyone care what the credit ratings agencies say?

First, a downgrade by a credit ratings agency or a negative outlook provides a tangible signal for investors when intangible things—such as political negotiations—are going badly. Second, ratings downgrades can trigger huge sell-offs for funds that passively track indices based on the big agencies' ratings.

To compensate for being behind the curve at the outset of the global financial crisis, it seems the three agencies have been over-eager to downgrade or threaten to downgrade countries in Europe and the US in recent weeks.

Flurry of downgrades in Europe

On 5 July, Moody's downgraded Portugal to junk status with a negative outlook. A week later on 12 July, Moody's downgraded Ireland to junk with a negative outlook as well. On 13 July, Fitch downgraded Greece to a rating of CCC, just above default.

These downgrades came at seemingly random times. The press release to announce Portugal's downgrade spoke primarily of developments in Greece. The presser accompanying Ireland's downgrade referred mostly to developments at the EU level. Fitch's downgrade of Greece occurred just after EU leaders and the IMF had committed to agreeing a second bailout for the country, a positive development by all accounts.

The specific timings of the downgrades seemed random, but they did reflect two aspects of the euro crisis that EU leaders themselves have not yet managed to fully grasp: the swiftness and force with which the euro crisis can spread from one country to another and the role that dithering at the EU level serves to catalyse this.

The credit ratings agencies have put significant pressure on peripheral eurozone countries already snapping under the weight of harsh austerity programmes. They are also influencing fiscal policy at the EU level. Earlier this month, the main agencies poured cold water on a number of different proposals for involving the private sector in a second bailout package for Greece.

Livid about the influence of the main ratings agencies on investors, European commission president Jose Emanuel Barroso and other policy makers have called for the creation of a European rating agency. The most common argument is that the three main ratings agencies are all based in the US, and therefore have vested interests that are not aligned with those of the EU.

In reality, only Moody's and Standard & Poor's are based in the US, while Fitch is majority owned by a French company.

Influence in the US

Furthermore, the three main agencies have proven they are willing to ruffle feathers in the US as well, despite their investor base being largely American.

On 13 July, Moody's placed the US on a negative watch and said it would downgrade the country if the US missed any debt payments. A few days later, Standard & Poor's also warned there was a 50-50 chance it would downgrade the US if a deal on increasing the US debt ceiling is not agreed soon. On 18 July, Fitch jumped on the bandwagon to say that failure to reach a deal on the debt ceiling by 2 August would cause it to place the US on negative watch.

The past week has been characterized by tense negotiations between the Republicans and the Obama administration about the debt ceiling, but there has been no particular spark to justify this recent flurry of ratings agency threats. Instead, it seems the three main agencies aim to put pressure on US politicians to find agreement on the debt ceiling.

Still not to blame

While the credit ratings agencies arguably have too much influence over fiscal policy in the eurozone and the US and a downgrade or a threat to downgrade can influence markets, the agencies cannot be blamed for the debt crises on either side of the Atlantic.

As a country comes under pressure in the markets, the onus is on that country's government to ensure that it implements the policies necessary to restore confidence in credit ratings agencies and investors alike.

Downgrades by credit ratings agencies, no matter how spurious the timing may seem, cannot be considered a fundamental cause of the debt crisis in either Europe or the US. Perhaps Citibank's chief economist Willem Buiter put it best when he said that blaming the credit ratings agencies was like throwing out a thermometer just because it showed you had a fever. No good comes of shooting the messenger.

Dr Megan Greene, formerly of the Economist Intelligence Unit, is a consultant economist specialising in the euro crisis. For more information: www.economistmeg.com